HOLLOMAN AIR FORCE BASE, N.M. -- Staff Sgt. Zachery Doering, 49th Maintenance Squadron nondestructive inspection specialist, uses a swab to point to a crack, illuminated with penetrant, in the main thrust mount pin while performing a magnetic particle inspection at the base NDI shop, Feb. 11. A magnetic particle inspection reveals any surface and subsurface defects of magnetic metal items. (U.S. Air Force photo/Senior Airman Tiffany Trojca)